Research Of The Complexes' Syntheses, Structures And Properties Based On Aromatic Polycarboxylates And N-containing Co-Ligands

Crystal engineering in the basis of metal-organic frameworks (MOFs) has caused considerable attention, not only for their elegant framework topologies but also due to their applications in practical production, such as optoelectronic devices, hydrogenstorage, molecular magnetism, and catalysis, ect. In this regard, rational design and construction of new materials with specific properties has become a particularly important and topical subject. In order to assemble these molecular structures, carboxylate ligands are frequently employed to construct coordination polymers as bridging ligands to fit the synthetic flexibility and variation of the metal centers due to their versatile coordination properties and high structural stability. On the other hand, a fairly effective way to construct desirable networks is the introduction of multidentate flexible N-donor ligands, such as 1,2-bis(4-pyridyl)-ethane,1,3-bis(4-pyridyl)-propane, 1,2-bis(imidazol)-ethane,1,3-bis(imidazol)-propane,1,4-bis(imidazol)-butane and so on. Their flexibility can result not only in gauche and anti conformations in coordination, but also in free rotation to meet the requirements of the coordination geometry of the metal ions in the assembly process. In this work, we employed 5-substituted dicarboxylates, 5-NO2-1,2,3-benzenetricarboxylate and a series of N-containing co-ligands to react with the divalent transition metal ions to research the influence of the different functional groups on the topologies and properties of the coordination networks under different conditions. Nineteen coordination polymers have been successfully synthesized via hydrothermal reactions and studyed by IR spectra, X-ray single crystal analysis, elemental analysis. Their fluorescence and magnetic properties have also been measured.1. Four new NiⅡand CoⅡcomplexes, [Ni(5-Br-ip)(bip)(H2O)]n (1), [Ni(5-Br-ip)(bib)]n (2), [Co(5-Br-ip)(bip)]n (3), and [Co(5-Br-ip)(bip)]n (4) have been synthesized via hydrothermal reactions and characterized by elemental analysis and IR spectra. Moreover, magnetic properties of complexes 2 and 3 were investigated.2. Six new CuⅡ, CoⅡand NiⅡcoordination complexes, [Cu2(mip)2(bpa)]n (5), [Cu2(mip)2(bpe)]n (6),{[Co2(mip)2(bpa)2]}n (7),{[Co2(mip)2(bpp)2]}n (8), {[Ni(mip)(bpa)]}n (9), as well as {[Ni(mip)(bpp)(H2O)]}n (10), were obtained by hydrothermal reactions based on H2mip and different dipyridyl ligands. The structures of these complexes were investigated by single-crystal X-ray diffraction analyses and then determined by IR spectra and elemental analyses. The variable-temperature magnetic susceptibility studies shown that the antiferromagnetic interactions among the CuⅡions (5) and Co11 ions (8) and the ferromagnetic interactions among the NiⅡions in 9 and 10 are exist.3. Seven new Zn(Ⅱ) and Cd(Ⅱ) coordination complexes, {[Zn2(5-Br-ip)2(bpy)(H2O)]·2H2O}n (11).{[Zn(5-Br-ip)(bpa)(H2O)]}n (12), {[Cd(5-Br-ip)(bpp)(H2O)]}n (13),{[Zn(5-Br-ip)(bpe)]}n (14), {[Zn2(4-Br-ip)2(bpy)]·H2O}n (15),{[Zn(4-Br-ip)(bpa)(H2O)]}n (16), and {[Cd(4-Br-ip)(bpp)]}n (17) were synthesized by hydrothermal reactions from 4-Br-ip2- and 5-Br-ip2-. And the results show that the position of the -Br group in this kind of dicarboxyl blocks plays an important positional isomeric effect in the construction of the coordination frameworks. Furthermore, the photoluminescent properties of the seven complexes have been investigated.4. Two new Co(Ⅱ) and Cu(Ⅱ) complexes,{[Co(O2N-Hbtb)(phen)(H2O)3]·2H2O}n (18) and {[Cu3(O2N-btb)2(bipy)2(H2O)4]·4H2O}n (19) have been synthesized via the reaction of O2N-H3btb and different N-containing auxiliary ligands. Their crystal structures and the magnetic properties of complex 19 were also studied. The magnetic susceptibility studies indicated that between the polymeric CuⅡions ferromagnetic interactions were existence.